Acrylic block copolymer adhesives

ABSTRACT

Adhesive compositions and articles containing the adhesive compositions are provided. In some embodiments, the adhesive compositions can be positioned adjacent to biological surfaces such as skin. For example, articles are provided that can be used in wound dressing or that can be used to stabilize and/or affix a medical device or medical instrument to a patient.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication No. 62/052673, filed Sep. 19, 2014, the disclosure of whichis incorporated by reference herein in its entirety.

TECHNICAL FIELD

The disclosure relates to an adhesive that includes an acrylic blockcopolymer composition and to an article that includes the adhesive.

BACKGROUND

Adhesives have many commercial applications. Block copolymers have beenused in adhesives such as those described, for example, in U.S. Pat. No.6,723,407 (Dollase et al.), U.S. Pat. No. 5,711,940 (Kuentz), U.S. Pat.No. 6,734,256 (Everaerts et al.), and U.S. Pat. No. 7,255,920 (Everaertset al.).

U.S. Patent Application Publication 2013/0079468 (Kanemura et al.)describes a pressure-sensitive adhesive composition that is suitable foroptical film. This adhesive contains “a specific acrylic diblockcopolymer (I) and a specific acrylic triblock copolymer (II) in aspecific proportion.” The mass ratio of the acrylic diblock copolymer(I) to the acrylic triblock copolymer (II) is in the range of 70/30 to30/70. The adhesive “exhibits durability by virtue of rise of adhesivestrength when the optical film is kept in the applied state over a longperiod of time after application.”

While a variety of adhesives are known, not all adhesives are suitablefor applications that require adhesion to biological surfaces such asskin.

SUMMARY

Adhesive compositions and articles containing the adhesive compositionsare provided. In some embodiments, the adhesive compositions can bepositioned adjacent to biological surfaces such as skin. For example,articles are provided that can be used in wound dressing or that can beused to stabilize and/or affix a medical device or medical instrument toa patient.

In a first aspect, an adhesive is provided that can comprise:

-   -   (a) an acrylic triblock copolymer A-B-A comprising from 20% to        55% by weight A blocks and 45% to 80% by weight B block; and    -   (b) an acrylic diblock copolymer A-B comprising from 5% to 30%        by weight A block and 70% to 95% by weight B block, wherein

each A block is independently a polymeric block having a glasstransition temperature of at least 50° C.;

each A block independently comprises at least one poly(meth)acrylate;

each B block is independently a polymeric block having a glasstransition temperature no greater than 20° C.;

each B block independently comprises at least one poly(meth)acrylate;and

the weight ratio of the acrylic diblock copolymer to the acrylictriblock copolymer is from 65:35 to 90:10.

In a second aspect, an article is provided that comprises a substrateand an adhesive layer positioned adjacent to the substrate. The adhesivelayer contains the adhesive described above.

In a third aspect, a wound dressing is provided that comprises anadhesive as described above.

In a fourth aspect, a method of using the adhesive is provided thatincludes affixing or stabilizing a medical device to a patient usingwith an adhesive as described above.

DETAILED DESCRIPTION

Adhesive compositions and articles containing the adhesive compositionsare provided. In some embodiments, the adhesive compositions can bepositioned adjacent to biological surfaces such as skin. For example,articles are provided that can be used in wound dressing or that can beused to stabilize and/or affix a medical device or medical instrument toa patient.

Throughout the disclosure, singular forms such as “a,” “an,” and “the”are often used for convenience. However, it is to be understood thatsuch singular forms include the plural unless the singular alone iseither specified or clearly called for by context.

“Copolymer” and conjugations (variations) thereof each refer to apolymer having more than one type of repeating unit.

“Block copolymer” and conjugations thereof each refer to a linearcopolymer having a plurality of segments, known as polymeric “blocks”.Each block includes multiple monomeric units and different blockscontain different types of monomeric units. The boundary betweenadjacent blocks can be sharp, wherein the composition of the monomericunits changes abruptly, or tapered, wherein there is a mixing regionbetween the blocks containing monomeric units from both of the adjacentblocks. The term “block copolymer”, including both its plural andconjugate forms, may be written with standard numerical prefixes toindicate the number of blocks. Thus, “diblock copolymer” and “triblockcopolymer” are block copolymers with two and three blocks, respectively.Star copolymers, graft copolymers, comb copolymers, dendrimers, andother macromolecules with substantially non-linear architectures are notblock copolymers as that term is used herein.

“Da” is an abbreviation for “Dalton” or its plural, “Daltons” and is anaccepted unit of molecular weight. The abbreviation Da may be modifiedby typical prefixes indicating orders of magnitude, for example, kDa isan abbreviation for kilo Dalton. “Homopolymer” and its conjugationsthereof each refer to a polymer or a block of a block copolymer that iscomposed substantially of a single polymerized monomer. As used in thiscontext, being composed substantially of a single polymerized monomermeans that no more than incidental or trace amounts of other monomers,such as impurities, can be present.

“(Meth)acrylate” and conjugations thereof each refer to esters of(meth)acrylic acid. (Meth)acrylates are often alkyl (meth)acrylate, aryl(meth)acrylates, or aralkyl (meth)acrylates.

“(Meth)acrylic acid” and conjugations thereof each refer to one or moreof methacrylic acid and acrylic acid.

“Alkyl” refers to a saturated monovalent hydrocarbon radical. Alkylradicals can be linear, branched, cyclic, or a combination thereof(e.g., an alkyl radical can have a cyclic portion and a linear orbranched portion). Alkyl radicals can have any suitable number of carbonatoms. For example, alkyl radicals can be from C₁ to C₂₂. Some alkylradicals are C₁ or greater, C₂ or greater, C₃ or greater, C₄ or greater,C₆ or greater, or C₈ or greater. Some alkyl radicals are C₂₂ or smaller,C₂₀ or smaller, C₁₈ or smaller, C₁₆ or smaller, C₁₂ or smaller, Cio orsmaller, C₉ or smaller, C₈ or smaller, C₆ or smaller, or C₄ or smaller.

“Aryl” refers to a cyclic aromatic monovalent hydrocarbon radical. Arylradicals can have any suitable number of carbon atoms. Some arylradicals are C₆ or higher, C₁₀ or higher, or C₁₄ or higher. Some arylradicals are C₁₆ or smaller, C₁₄ or smaller, or Cio or smaller. Phenylis a common aryl radical.

“Aralkyl” refers to a monovalent radical having an aryl componentcovalently bound to an alkyl component. Aralkyl radicals are bound to amolecule, monomer, or polymer; the bond can be by way of an aryl carbonor an alkyl carbon. The aryl portion of an aralkyl radical can have anysuitable number of carbon atoms, such as those referred to above withrespect to the definition of aryl. Likewise, the alkyl portion of anaralkyl radical can have any suitable number of carbon atoms, such asthose referred to above with respect to the definition of alkyl.

“Chemical crosslinker” and conjugations thereof each refer to a chemicalcompound that has multiple reactive sites for forming covalent bondswith one or more existing or growing polymer chains. Chemicalcrosslinkers typically have two, three, or more ethylenicallyunsaturated groups. Monomers such as (meth)acrylates that have only oneethylenically unsaturated group are not chemical crosslinkers, eventhough such monomers can form crosslinked polymers by way of, forexample, chain transfer reactions.

“Acrylic polymer” including conjugations thereof each refer to a polymeror block made up of a polymerized product of one or more of monomershaving a (meth)acryloyl group, which is a group of formula H₂C═CR—(CO)—where R is hydrogen or methyl and refers to a methacryloyl, an acryloylgroup, or both. Suitable monomers include, for example, (meth)acrylicacid, (meth)acrylate, (meth)acrylamide, N-alkyl (meth)acrlyamide,N-dialkyl (meth)acrylamide, N-trialkyl (meth)acrylamide, and hydroxysubstituted alkyl (meth)acrylate. Acrylic polymers can also containpolymerized or partially polymerized forms of one or more chemicalcrosslinkers. Only incidental or trace amounts of other materials, suchas impurities, are present in the chemical structure of acrylicpolymers.

“Acrylic block copolymer” including conjugations thereof each refer toblock copolymers wherein each polymeric block is an acrylic polymer. Anumerical prefix may be used to identify the number of blocks, thus“acrylic diblock copolymers” and “acrylic triblock copolymers” have twoand three blocks, respectively. No other types of polymeric blocks, suchas styrene blocks, olefinic blocks, or vinyl ester blocks, are presentin acrylic block copolymers.

The prefix “poly” before the name of a monomer refers to a polymer orpolymer block that is predominantly made up of a polymerized version ofthe specified monomer. In this context, “predominantly made up of” meansthat at least 80%, at least 85%, at least 90%, at least 95%, or at least99% of the repeat units in the polymer or polymer block are polymerizedversions of the specified monomer. The remainder of the polymer orpolymer block can include polymerized versions of monomers other thanthe specified monomer.

The terms “adhesive” and “adhesive composition” are usedinterchangeably.

“Independently” when used in reference to an element that appears inmultiple instances means that each instance of the element can be thesame or different. For example, if element E appears in two instancesand can be independently X or Y, then the first and second instances ofelement E can be, respectively, X and X, X and Y, Y and X, or Y and Y.

“Edge lift” refers to the disjoining of an article, such as an adhesivearticle, from an adherent.

Adhesives for use in applications that require adhesion to biologicalsurfaces such as skin can have a combination of properties that can beunacceptable for other applications. Adhesives to be used on the skincan have low shear to allow easy removal of the adhered article.However, for use in many applications, adhesives should also havesufficient tack to adhere an article to skin without significant edgelift for a sufficient period of time (e.g., 1 day to 2 weeks or more).Furthermore, adhesives for use on the skin or other biological surfaceshould not leave unacceptable levels of residue on the skin orbiological surface after being removed. Thus, one technical problem tobe solved is to formulate an adhesive for use on skin that has improvedproperties in these regards. However, it is to be understood that theadhesive composition, articles containing the same, and methods of usingthe same, may also address or solve other technical problems. Thus, thescope of protection sought is not to be limited by this technicalproblem.

The above problem can be solved by using an adhesive having a particularacrylic triblock copolymer and a particular acrylic diblock copolymer ina particular ratio. In particular, such adhesive can comprise:

-   -   (a) an acrylic triblock copolymer A-B-A comprising from 20% to        55% by weight A blocks and 45% to 80% by weight B block; and    -   (b) an acrylic diblock copolymer A-B comprising from 5% to 30%        by weight A block and 70% to 95% by weight B block, wherein

each A block is independently a polymeric block having a glasstransition temperature of at least 50° C.;

each A block independently comprises at least one poly(meth)acrylate;

each B block is independently a polymeric block having a glasstransition temperature no greater than 20° C.;

each B block independently comprises at least one poly(meth)acrylate;and

the weight ratio of the acrylic diblock copolymer to the acrylictriblock copolymer is from 65:35 to 90:10.

Further, an adhesive article comprising such a composition and methodsof using the same are also solutions to this problem.

Various unexpected effects and advantages can be obtained by way ofthese solutions. One such effect is that the resulting adhesivecompositions can have excellent adhesion to skin over a sufficientperiod of time while being removable without leaving an unacceptableamount of residue on the skin. Also, the resulting adhesive compositionscan have low shear holding time when measured on stainless steel. Thatan adhesive composition can have this combination of properties issurprising, because low shear holding time is typically associated withadhesives that have low cohesive strength, whereas a low amount ofresiduals is typically associated with adhesives that have high cohesivestrength.

The adhesive compositions can be adhered to the skin without significantedge lift for a period of one day to 2 weeks or more. Depending on theapplication, this period of time can be one day or more, two days ormore, three days or more, four days or more, five days or more, six daysor more, or seven days or more. For some applications, the period oftime is two weeks or less, thirteen days or less, twelve days or less,eleven days or less, ten days or less, nine days or less, or seven daysor less. For some applications, the period of time is one week.

The adhesive compositions can be useful for adhering articles, such asbandages, wound dressings, medical devices or instruments, and the like,to biological surfaces such as skin, as well as to other surfaces.Stated differently, various adhesive-containing articles are providedthat include the adhesive compositions such as, for example, bandages,wound dressings, adhesive tape, and the like. Such adhered articles canbe readily removed, for example, because of the low shear of theadhesive.

An adhesive composition can comprise an acrylic triblock copolymer A-B-Aand an acrylic diblock copolymer A-B. Each A can be, independently, apolymer block having a glass transition temperature of at least 50° C.and, independently, can comprise at least one poly(meth)acrylate. Each Bcan be, independently, a polymeric block having a glass transitiontemperature no greater than 20° C. and, independently, can comprise atleast one poly(meth)acrylate.

The glass transition temperature can be determined from dynamicalmechanical measurements. These measurements can be conducted using arheometer in a shear geometry. For example, the polymeric sample can betested in a parallel plate rheometer by heating from −50° C. to 200° C.at a rate of 2° C./minute and at a frequency of 1 radian/second. Thestorage modulus (G′), the loss modulus (G″), and tan δ (G″/G′) areplotted versus temperature. At very low temperatures (<−50° C.), theentire polymeric material is in a glassy state and is predominatelyelastic. A precipitous drop is observed in the storage modulus (G′) overa temperature range from about −50° C. to about 0° C. or from about −50°C. to about 20° C. A peak in tan δ is observed that is associated withthe Tg of the B block. That is, the peak occurs at the glass transitiontemperature of the B block. Above about 50° C., the storage modulusdrops due to the onset of polymeric flow and as the glass transitiontemperature of the A blocks are exceeded. A steep increase in tan δ isobserved that is associated with the Tg of the A blocks. That is, thesteep increase in tan δ occurs at the glass transition temperature ofthe A blocks.

The acrylic triblock copolymer can contain particular amounts of the Ablocks and the B block. For example, the acrylic triblock copolymer(A-B-A) can have an A block content, that is, the total content of bothA blocks taken together, that is from 20% to 55% by weight. In somecases, the A block content of the acrylic triblock copolymer is at least20% by weight, at least 25% by weight, at least 30% by weight, at least35% by weight, at least 40% by weight, or at least 50% by weight. Insome cases, the A block content of the acrylic triblock copolymer is nomore than 55% by weight, no more than 50% by weight, no more than 45% byweight, no more than 40% by weight, no more than 35% by weight, no morethan 30% by weight, or no more than 25% by weight.

Each of the two A blocks of the acrylic triblock copolymer can be aboutthe same weight. That is, the weight ratio of the two A blocks of theacrylic triblock copolymer is often 1:1. However, other weight ratioscan also be used. In many cases, the weight ratio of the two A blocks ofthe acrylic triblock copolymer is no lower than 0.65:1, 0.7:1, 0.75:1,0.8:1, 0.85:1, 0.9:1, or 0.95:1.

The B block content of the acrylic triblock copolymer can be from 45% to80% by weight. The B block content of the acrylic triblock copolymer canbe at least 45% by weight, at least 50% by weight, at least 55% byweight, at least 60% by weight, at least 65% by weight, at least 70% byweight, or at least 75% by weight. The B block content of the acrylictriblock copolymer can be no more than 80% by weight, no more than 75%by weight, no more than 70% by weight, no more than 65% by weight, nomore than 60% by weight, no more than 55% by weight, or no more than 50%by weight.

The acrylic triblock copolymer can have a number average molecularweight, M_(n), that is no less than 25 kDa, for example, no less than 30kDa, no less than 35 kDa, no less than 40 kDa, no less than 45 kDa, orno less than 50 kDa. The acrylic triblock copolymer can have a M_(n)that is no greater than 150 kDa, for example, no greater than 140 kDa,no greater than 130 kDa, no greater than 120 kDa, no greater than 110kDa, or no greater than 100 kDa. Thus, in some cases the M_(n) of theacrylic triblock copolymer can be from 25 kDa to 150 kDa, such as from30 kDa to 140 kDa, from 35 kDa to 140 kDa, from 35 kDa to 130 kDa, from40 kDa to 130 kDa, from 40 kDa to 120 kDa, or from 45 kDa to 120 kDa.The polydispersity index, PDI, of the acrylic triblock copolymer istypically 1.5 or less, such 1.3 or less, 1.2 or less or 1.1 or less,although this is not required unless otherwise specified. Thus, theweight average molecular weight, M_(w), of the acrylic triblockcopolymer can be no less than 25 kDa, such as no less than 30 kDa, noless than 35 kDa, no less than 40 kDa, no less than 50 kDa, or no lessthan 55 kDa. The acrylic triblock copolymer can have an M_(w) that is nogreater than 160 kDa, for example, no greater than 150 kDa, no greaterthan 140 kDa, no greater than 130 kDa, no greater than 120 kDa, or nogreater than 110 kDa. Exemplary ranges of the M_(w) of the acrylictriblock copolymer can be from 25 kDa to 160 kDa, such as from 30 kDa to150 kDa, from 35 kDa to 150 kDa, from 40 kDa to 140 kDa, from 40 kDa to130 kDa, from 40 kDa to 120 kDa, from 50 kDa to 140 kDa, from 50 kDa to130 kDa, from 50 kDa to 120 kDa, from 55 kDa to 120 kDa, or from 50 kDato 110 kDa.

The acrylic diblock copolymer can contain specific amounts of the Ablock and the B block. For example, the acrylic diblock copolymer canhave an A block content that is from 5% to 30% by weight. In some cases,the A block content of the acrylic diblock copolymer can be no less than5% by weight, no less than 10% by weight, no less than 15% by weight, noless than 20% by weight, or no less than 25% by weight. In some cases,the A block content of the acrylic diblock copolymer can be no greaterthan 30% by weight, no greater than 25% by weight, no greater than 20%by weight, no greater than 15% by weight, or no greater than 10% byweight.

The B block content of the acrylic diblock copolymer can be from 70% to95% by weight. In some cases, the B block content of the acrylic diblockcopolymer can be no less than 70% by weight, no less than 75% by weight,no less than 80% by weight, no less than 85% by weight, or no less than90% by weight. In some cases, the B block content of the acrylic diblockcopolymer can be no greater than 95% by weight, no greater than 90% byweight, no greater than 85% by weight, no greater than 80% by weight, nogreater than 75% by weight, or no greater than 70% by weight.

The acrylic diblock copolymer can have a particular number averagemolecular weight, M_(n), from that is no less than 25 kDa, no less than35 kDa, no less than 40 kDa, no less than 45 kDa, or no less than 50kDa. The M_(n) of the acrylic diblock copolymer can be no greater than100 kDa, no greater than 85 kDa, no greater than 80 kDa, no greater than75 kDa, no greater than 70 kDa, no greater than 65 kDa, or no greaterthan 60 kDa. Exemplary ranges for the M_(n) of the acrylic diblockcopolymer include, but are not limited to, 25 kDa to 100 kDa, such asfrom 25 kDa to 90 kDa, from 25 kDa to 80 kDa, from 25 kDa to 70 kDa,from 25 kDa to 60 kDa, from 35 kDa to 90 kDa, from 35 kDa to 80 kDa,from 30 kDa to 70 kDa, from 35 kDa to 60 kDa, from 40 kDa to 90 kDa,from 40 kDa to 80 kDa, from 40 kDa to 70 kDa, or from 40 kDa to 60 kDa.The polydispersity index of the acrylic diblock copolymer is typically1.5 or less, such 1.3 or less, 1.2 or less or 1.1 or less, although thisis not required unless otherwise specified. Thus, the weight averagemolecular weight, M_(w), of the acrylic diblock can be no less than 30kDa, no less than 35 kDa, or no less than 40 kDa. Similarly, the M_(w)of the acrylic diblock can be no more than 125 kDa, no more than 100kDa, no more than 90 kDa, or no more than 80 kDa. Exemplary ranges forM_(w) of the acrylic diblock can be from 30 kDa to 125 kDa, 30 kDa to100 kDa, from 30 kDa to 90 kDa, from 30 kDa to 80 kDa, from 40 kDa to125 kDa, from 40 kDa to 100 kDa, or from 40 kDa to 90 kDa.

The A blocks of the acrylic diblock copolymer, the acrylic triblockcopolymer, or both the acrylic diblock copolymer and the acrylictriblock copolymer can be hard blocks in that they can have greaterrigidity than that of the B blocks. Thus, the A blocks can have a higherglass transition temperature than the B blocks. The A blocks can bethermoplastic, and can provide structural strength, cohesive strength,or both, to the adhesive.

The B blocks of the acrylic diblock copolymer, the acrylic triblockcopolymer, or both the acrylic diblock copolymer and the acrylictriblock copolymer can be soft blocks in that they can have greaterelasticity than the A blocks. Thus, the B blocks can have lower glasstransition temperatures than the A blocks. The B blocks can beelastomeric.

While a variety of polymer types can be used as the A block and the Bblock, in many cases the A blocks are a poly(methacrylate) such as apoly(alkyl methacarylate) and the B blocks is a poly(acrylate) such as apoly(alkyl acrylate).

One or more of the various blocks can be a homopolymer. For example, theA block of the acrylic diblock copolymer can be homopolymer. Also, oneof the A blocks of the acrylic triblock copolymer can be a homopolymer,or both of the A blocks of the acrylic triblock copolymer can behomopolymeric. Further, the B block of the acrylic diblock copolymer,the acrylic triblock copolymer, or both the acrylic diblock copolymerand the acrylic triblock copolymer can be a homopolymer.

A variety of polymer blocks can be independently used as the A blocks inthe acrylic diblock copolymer, the acrylic triblock copolymer, or boththe acrylic diblock copolymer and the acrylic triblock copolymer inorder to provide a rigid A block having a glass transition temperatureof at least 50° C. In many cases, such A blocks include one or more ofpoly(alkyl (meth)acrylate), poly(aryl (meth)acrylate), and poly(aralkyl(meth)acrylate). Most commonly, one or more poly(alkyl (meth)acrylates)are used. The alkyl groups in the poly(alkyl (meth)acrylate) can be anysuitable alkyl group that produces an A block having the requisite glasstransition temperature, such as one or more of methyl, ethyl, isopropyl,tent-butyl, sec-butyl, iso-butyl, cyclohexyl, isobornyl, and3,3,5-trimethylcyclohexyl. In some cases, C₁ to C₃ alkyl can be used. Insome cases, the (meth)acrylate is a methacrylate. Typical methacrylatesinclude poly(methyl methacrylate), poly(ethyl methacrylate),poly(n-propyl methacrylate), poly(isopropyl methacrylate), poly(n-butylmethacrylate), poly(sec-butyl methacrylate), poly(isobutylmethacrylate), poly(tert-butyl methacrylate), poly(isobornylmethacrylate), poly(n-hexyl methacrylate), poly(cyclohexylmethacrylate), poly(2-ethylhexyl methacrylate), poly(n-octylmethacrylate), poly(isobornyl (meth)acrylate), andpoly(3,3,5-trimethylcyclohexyl methacrylate). Poly(methyl methacrylate)is most common, but no specific polymer is required, so long as the Ablock has the requisite glass transition temperature.

Stated differently, each A block can be prepared from any suitablemonomer or monomer mixture provided the resulting block has a glasstransition temperature of at least 50° C. The monomers used to form eachA block are often selected from an alkyl methacrylate (e.g., thosehaving an alkyl group with 1 to 10 carbon atoms or 1 to 6 carbon atoms),an aryl methacrylate (e.g., an aryl having 5 or 6 carbon atoms), or anaralkyl methacrylate (e.g., those having an aralkyl group with 7 to 12carbon atoms or 7 to 10 carbon atoms). Example monomers include, but arenot limited to, methyl methacrylate, ethyl methacrylate, propylmethacrylate, n-butyl methacrylate, sec-butyl methacrylate, isobutylmethacrylate, tent-butyl methacrylate, n-hexyl methacrylate, cyclohexylmethacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, and3,3,5-trimethylcyclohexyl methacrylate, isobornyl (meth)acrylate, phenylmethacrylate, and benzyl methacrylate. In many embodiments, the monomerused to form each A block is methyl methacrylate.

In some embodiments, the A block can be formed from a monomer mixturecontaining an alkyl methacrylate and up to 20% by weight of one or moreadditional acrylic monomers, such as an (meth)acrylamide, (meth)acrylicacid, or hydroxy-substituted alkyl (meth)acrylate. In such cases, the Ablock is typically a random copolymer that contains up to 20% by weight,up to 10% by weight, up to 5% by weight, or up to 1% by weight of theone or more additional acrylic monomers that are randomly distributedthroughout the A block. For example, the A block can contain 80 to 99%by weight of an alkyl methacrylate and 1 to 20% by weight of theadditional acrylic monomer or 90 to 99% by weight of an alkylmethacrylate and 1 to 10% by weight of the additional acrylic monomer.These one or more additional monomers are typically polar, and can beadded to one or more of the A blocks to adjust the glass transitiontemperature and cohesive strength of the A blocks.

The various A blocks can be the same or different. Thus, the two Ablocks in the acrylic triblock copolymer can be the same or differentfrom each other. Further, each of the two A blocks in the acrylictriblock copolymer can be the same or different from the A block in theacrylic diblock copolymer. The two A blocks in the acrylic triblockcopolymer are often the same. Also, the A blocks in the acrylic diblockcopolymer are often the same as the A blocks in the acrylic triblockcopolymer, however this is not required unless otherwise specified. Whenthe two A blocks in the acrylic triblock copolymer are the same as eachother or the same as the A block in the acrylic diblock copolymer, thecompatibility between the various A blocks can be maximized.

The glass transition temperature of any of the A blocks is at least 50°C., however, it can also be at least 60° C., at least 80° C., at least100° C., at least 120° C., or higher. In addition, the glass transitiontemperature of the A blocks is often no greater than 200° C., no greaterthan 190° C., or no greater than 180° C. Exemplary ranges of glasstransition temperatures of the A blocks include 50° C. to 200° C., 60°C. to 200° C., 80° C. to 200° C., 80° C. to 180° C., or 100° C. to 180°C.

A variety of polymers can be independently used as B blocks in order toprovide a flexible block having a glass transition temperature of nomore than 20° C. Typically, such polymers comprise one or more ofpoly(alkyl (meth)acrylate), poly(aryl (meth)acrylate), poly(aralkyl(meth)acrylate), or poly((meth)acrylic acid). In many embodiment, the Bblock is a poly (alkyl (meth)acrylate). In particular, the B block isoften a poly(alkyl acrylate). The alkyl group of the alkyl(meth)acrylate can be any suitable alkyl group that produces a B blockhaving the requisite glass transition temperature. In some cases, thealkyl can be one or more C₂ to C₂₀ alkyl, for example one or more C₂ toC₁₆ alkyl, one or more C₄ to C₁₂ alkyl, one or more C₄ to C₉ alkyl, orone or more C₄ to C₈ alkyl. Typical examples include one or more ofn-butyl, propyl, including any isomer thereof, hexyl, including anyisomer thereof, octyl (that is, C₈ alkyl), including any isomer thereof,or nonyl (that is, C₉ alkyl), including any isomer thereof. While anyoctyl isomer can be used, isooctyl (i.e., 1-methylheptyl), 2-octyl, and2-ethylhexyl are common. Bicyclo [2.2.2] octyl can also be used. Whileany nonyl isomer can be used, isononyl is common. Thus, the B block isoften poly(n-butyl acrylate), poly(sec-butyl acrylate), poly(isobutylacrylate), poly(n-propyl acrylate), poly(isopropyl acrylate),poly(l-methylheptyl acrylate), poly(2-ethylhexyl acrylate),poly(isooctyl acrylate), poly(2-octyl acrylate), poly(isononylacrylate), or poly(bicyclo [2.2.2] octyl acrylate). Poly (n-butylacrylate) is common.

Stated differently, the B block can be prepared from any suitablemonomer or monomer mixture provided the resulting block has a glasstransition temperature is no more than 20° C. Examples alkyl acrylatesinclude, but are not limited to, n-butyl acrylate, decyl acrylate,2-ethoxy ethyl acrylate, 2-ethoxy ethyl methacrylate, isoamyl acrylate,n-hexyl acrylate, n-hexyl methacrylate, isobutyl acrylate, isodecylacrylate, isodecyl methacrylate, isononyl acrylate, 2-ethylhexylacrylate, 2-ethylhexyl methacrylate, isooctyl acrylate, isotridecylacrylate, lauryl acrylate, 2-methylbutyl acrylate, 4-methyl-2-pentylacrylate, n-octyl acrylate, 2-octyl acrylate, isononyl acrylate,n-propyl acrylate, 4-methylheptyl acrylate, and bicyclo [2.2.2]octylacrylate. Some methacrylates can be used such as isooctyl methacrylate,n-octyl methacrylate, and lauryl methacrylate. In many embodiments, themonomer used to form the B block is n-butyl acrylate.

Like the A blocks, the B block can be prepared from additional monomerssuch as the polar monomers that are described above. For example, the Bblock can be prepared from a monomer mixture that includes 80 to 99% byweight of an alkyl acrylate and 1 to 20% by weight of the additionalacrylic monomer or 90 to 99% by weight of an alkyl acrylate and 1 to 10%by weight of the additional acrylic monomer.

While the B blocks in the acrylic triblock copolymer and acrylic diblockcopolymer can be selected from the same group of polymerized monomers,the various B blocks can be the same or different. Thus, the B block ofthe acrylic diblock copolymer can be the same as or different from the Bblock of the acrylic triblock copolymer. In many cases, the B block ofthe acrylic diblock copolymer is the same as the B block of the acrylictriblock copolymer. Using B blocks of the acrylic diblock copolymer thatare the same as the B blocks of the acrylic triblock copolymer canmaximize the compatibility of the various B blocks.

The glass transition temperature of the B blocks is no more than 20° C.,however, it can also be no more than 10° C., no more than 5° C., no morethan 0° C., no more than −10° C., no more than −20° C., no more than−30° C., no more than −40° C., no more than −50° C., or no more than−75° C. Exemplary ranges for the glass transition temperature of the Bblocks include −20° C. to 20° C., −20° C. to 10° C., −50° C. to 0° C.,and −50° C. to 10° C.

The acrylic triblock copolymer and acrylic diblock copolymer can besynthesized by any suitable technique. Suitable techniques can includeanionic polymerization, radical polymerization, group transferpolymerization, and ring-opening polymerization. The polymerization canbe a “living” or “controlled/living” polymerization, which can have theadvantage of producing block copolymer structures that are well defined.Specific examples include atom transfer radical polymerization (ATRP)and reversible addition-fragmentation chain transfer polymerization(RAFT).

Living polymerization techniques can lead to more stereoregular blockstructures than blocks prepared using non-living or pseudo-livingpolymerization techniques, such as polymerization reactions that useiniferters. Stereoregularity can be evidenced by highly syndiotactic orisotactic structures, and can result in well-controlled blockstructures. Such structures can influence the glass transitiontemperature of the block. For example, syndiotactic poly(methylmethacrylate) (PMMA) synthesized using living polymerization techniquescan have a glass transition temperature that is as much as 20° C. to 25°C. higher than comparable atactic PMMA synthesized using non-livingpolymerization techniques. Thus, the glass transition temperature of thevarious blocks of the block copolymers can depend on the blockcopolymers stereoregularity as well as on the monomer content of theblock copolymers. Stereoregularity can be detected, for example, usingnuclear magnetic resonance spectroscopy. Structures with greater thanabout 75 percent stereoregularity can often be obtained using living orcontrolled/living polymerization techniques, such as those discussedabove. No particular degree stereoregularity or tacticity is requiredfor any of the A or B blocks in the acrylic triblock copolymers oracrylic diblock copolymers, so long as the various A blocks and B blockshave the requisite glass transition temperatures.

Living polymerizations can also provide block copolymers with sharptransitions between the blocks. Block copolymers having A blocks and Bblocks can have regions on the boarder of an A block and a B block thatcontain a mixture of both A monomers and B monomers. When a livingpolymerization technique is used, the size of such regions can beminimized, or even eliminated, leading to a sharper transition from an Ablock to a B block, or from a B block to an A block. This can bebeneficial when phase separation of A blocks and B blocks is desired,because a region of mixed A and B monomeric units can be compatible withboth A and B blocks, thereby reducing the phase separation. On the otherhand, a sharp transition with minimal regions of mixed A and B monomericunits can promote phase separation.

When living polymerization techniques are used to form a block, themonomers can be contacted with an initiator in the presence of an inertdiluent. The inert diluent can facilitate heat transfer and mixing ofthe initiator with the monomers. Typically, the inert diluent is one ormore molecules that do not undergo a chemical reaction under thepolymerization conditions. Although any suitable inert diluent can beused, saturated hydrocarbons, aromatic hydrocarbons, ethers, esters,ketones, and combinations thereof are often selected. Exemplary inertdiluents include, but are not limited to, saturated aliphatic andcycloaliphatic hydrocarbons such as hexane, octane, cyclohexane, and thelike; aromatic hydrocarbons such as benzene, toluene, and xylene; andaliphatic and cyclic ethers such as dimethyl ether, diethyl ether,tetrahydrofuran, and the like; esters such as ethyl acetate, butylacetate, and the like; and ketones such as acetone, methyl ethyl ketone,methyl isobutyl ketone, and the like.

When block copolymers are prepared using living anionic polymerizationtechniques, the simplified structure A-M can represent a living A blockwhere M is an initiator fragment that is typically selected from a GroupI metal such as Li, Na, or K. The A block can be the polymerizationproduct of a first monomer composition that includes (meth)acrylatemonomers, such as alkyl methacrylates (e.g., methyl (meth)acrylate). Asecond monomer composition that includes the monomers used to form the Bblock can be added to A-M resulting in the formation of the livingdiblock structure A-B-M. The addition of another charge of the firstmonomer composition and the subsequent elimination of the living anionsite, for example, by quenching, can result in the formation of triblockstructure A-B-A. Alternatively, living diblock A-B-M structures can becoupled using difunctional or multifunctional coupling agents to formthe triblock structure A-B-A copolymers.

Any initiator known in the art for living anionic polymerizationreactions can be used. Typical initiators include alkali metalhydrocarbons such as organomonolithium compounds, examples of whichinclude ethyl lithium, n-propyl lithium, iso-propyl lithium, n-butyllithium, sec-butyl lithium, tert-octyl lithium, n-decyl lithium, phenyllithium, 2-naphthyl lithium, 4-butylphenyl lithium, 4-phenylbutyllithium, cyclohexyl lithium, and the like. Such initiators can bereferred to as mono functional initiators because each molecule ofinitiator produces one anion. Monofunctional initiators can be useful inthe preparation of a living A block or a living B block. For livinganionic polymerization of (meth)acrylates, the reactivity of the anioncan be tempered by the addition of one or more complexing ligands suchas one or more of lithium chloride, crown ethers, or lithioethoxylates.

The initiator in living anionic polymerizations is often added drop wiseto the monomers until a characteristic color that is typicallyassociated with the anion of the initiator persists. The preliminarydrop wise addition can destroy contaminants that react with initiator,thereby providing better control of the polymerization reaction. Then,the calculated amount of the initiator can be added to produce a polymerof the desired molecular weight. The amount of initiator needed for anyparticular molecular weight of polymer can be calculated by using aknown amount of monomer and assuming that each molecule of initiatorwill produce a single polymer chain, all of which will be of equallength. This assumption is reasonably accurate for many living anionicpolymerizations.

When the block copolymers are prepared using living free radicalpolymerization techniques, one or more free radical initiators can beused. Free radical initiators useful for living free radicalpolymerizations, as well as procedures for such polymerization, areknown; a detailed description can be found in International PatentApplication Publication Nos. WO 97/18247 (Matyjaszewski et al.) and WO98/01478 (Le et al.), as well as in the Handbook of RadicalPolymerization (Matyjaszewski et al.).

The polymerization temperature used depends on the monomers beingpolymerized and on the type of polymerization technique used. In manycases, appropriate reaction temperatures for polymerization range from−100° C. to 200° C. For living anionic polymerization reactions, theappropriate temperature is often from −80° C. to 20° C. For living freeradical polymerization reactions, the appropriate reaction temperatureis often from 20° C. to 150° C.

The polymerization reaction can be carried out under controlledconditions so as to exclude substances that can destroy the initiator,living radical, or living anion. Typically, the polymerization reactionis carried out in an inert atmosphere such as nitrogen, argon, helium,or combinations thereof, although this is not required in allcircumstances. When the reaction is a living anionic polymerization,anhydrous conditions can be used.

The adhesive composition can contain a particular ratio of diblockcopolymer to triblock copolymer on a weight basis. For example,depending on the particular application, the ratio of the acrylicdiblock copolymer to acrylic triblock copolymer can be from 65:35 to80:20, from 70:30 to 90:10, from 70:30 to 80:20, from 75:25 to 90:10, orfrom 75:25 to 80:20.

The relative amount of the acrylic diblock copolymer and the acrylictriblock copolymer can also be expressed as a weight percent of theacrylic diblock copolymer, the acrylic triblock copolymer, or both,relative to the total weight of the acrylic diblock copolymer and theacrylic triblock copolymer. Expressed in this manner, the amount ofacrylic diblock copolymer can be 65% by weight or greater, 70% by weightor greater, 80% by weight or greater, or 85% by weight or greater,relative to the total weight of the acrylic diblock copolymer and theacrylic triblock copolymer. In some cases, the amount of the acrylicdiblock copolymer can be no more than 90% by weight, no more than 85% byweight, no more than 80% by weight, no more than 75% by weight, or nomore than 70% by weight, relative to the total weight of the acrylicdiblock copolymer and the acrylic triblock copolymer. Likewise, theamount of the acrylic triblock copolymer can be 10% by weight orgreater, 15% by weight or greater, 20% by weight or greater, 25% byweight or greater, or 30% by weight or greater relative to the totalweight of the acrylic diblock copolymer and the acrylic triblockcopolymer. The amount of the acrylic triblock copolymer can also be nomore than 35% by weight, no more than 30% by weight, no more than 25% byweight, no more than 20% by weight, or no more than 15% by weightrelative to the total weight of the acrylic diblock copolymer and theacrylic triblock copolymer.

The adhesive composition is typically free of chemical crosslinkers.Nonetheless, it is possible for some covalent or chemical crosslinkingto occur, particularly if the adhesive composition is treated withradiation, in particular ionizing radiation, gamma radiation, or E-beamradiation. Depending on the intended use of the adhesive composition,such treatment can be desirable or even necessary, for example, as partof a sterilization process.

The chemical identity of the various A blocks and B blocks relates tothe glass transition temperatures of those blocks. In part because ofthe different glass transition temperatures of the A blocks and the Bblocks, the A blocks can have solubility parameters that aresufficiently different from those of the B block such that an A blockphase is separated from a B block phase. This phase separation can causethe adhesive composition to have a multiphase morphology at applicabletemperatures, and particularly at temperatures from ambient temperatureup to about 150° C. Thus, the adhesive composition can have distinctregions of hard A block domains, which can be nanodomains with sizes onthe order of nanometers or tens of nanometers, in a matrix of soft Bblock domains. Matrices of soft B block domains that have maximumcontinuity can be achieved by selecting a B block of the acrylictriblock copolymer that is highly compatible with the B block of theacrylic diblock copolymer. Thus, the B block of the acrylic triblockcopolymer is often selected to have the same chemical identity as the Bblock of the acrylic triblock copolymer.

The phase separated domains can have different morphologies depending onthe relative amounts of the A and B blocks in the acrylic diblockcopolymer and the acrylic triblock copolymer, as well as the ratio ofthe acrylic diblock copolymer to the acrylic triblock copolymer. Themultiphase morphology can give rise to physical crosslinking, wherebythe A blocks of the acrylic diblock copolymer associate with the Ablocks of the acrylic triblock copolymer and the B blocks of the acrylicdiblock copolymer associate with the B blocks of the acrylic triblockcopolymer. This physical crosslinking is different from chemicalcrosslinking in that physical crosslinking forms crosslinks bynon-covalent interactions, and not by the formation of covalent chemicalbonds. The extent or strength of the physical crosslinking can bemaximized by selecting A blocks of the acrylic triblock copolymer thatare highly compatible both with each other and with the A block of theacrylic diblock copolymer. Thus, the A blocks of the acrylic triblockcopolymer are often selected to have the same chemical identity as eachother, and are also often selected to have the same chemical identity asthe A block of the acrylic diblock copolymer.

In addition to relating to the chemical identity of the various A and Bblocks of the acrylic triblock copolymer and the acrylic diblockcopolymer, the extent of physical crosslinking and ultimate propertiesof the adhesive composition can also depend on the relative weights ofthe various A and B blocks of the acrylic triblock copolymer and theacrylic diblock copolymer. The nanodomains of the hard A block can beresponsible for physical crosslinking of the adhesive composition. Inparticular, the two A blocks of the acrylic triblock copolymer can actas physical crosslinkers for the acrylic diblock copolymer. Higheramounts of physical crosslinking can relate to increased cohesivestrength of the adhesive composition. As such, increasing the A blockcontent of the acrylic triblock copolymer, of the acrylic diblockcopolymer, or of both the acrylic triblock copolymer and the acrylicdiblock copolymer tends to increase the cohesive strength of theadhesive composition. Increasing the content of the acrylic triblockcopolymer tends to have the same effect. For this reason, an adhesivecomposition having an A block content of either the acrylic triblockcopolymer or the acrylic diblock copolymer that is lower than what isdescribed herein (or conversely, a B block content of either the acrylicdiblock copolymer or the acrylic triblock copolymer that is higher thanwhat is described herein) can have insufficient cohesive strength to becleanly removable (low residue).

The matrix formed by the B blocks in the adhesive composition can beresponsible for the tackiness of the adhesive compositions. Accordingly,an adhesive composition having a lower B block content (or conversely, ahigher A block content) of the acrylic triblock copolymer, acrylicdiblock copolymer, or both, than what is described herein can haveinsufficient tackiness to properly adhere to a substrate. The sameresult can occur when the amount of acrylic triblock copolymer is higherthan what is described herein, because increasing the amount of physicalcrosslinking also tends to decrease tackiness.

When the weight ratios of the A and B blocks in the acrylic diblockcopolymer or acrylic triblock copolymer are not within the specifiedranges, or when the weight ratio of the acrylic diblock copolymer to theacrylic triblock copolymer are not within the specified ranges, theadhesive composition may not have the desired properties. For example,if the weight ratio of the acrylic diblock copolymer to acrylic triblockcopolymer is greater than 90:10, the composition tends to not liftcleanly from the adherent, and can leave unacceptable amounts of residueon the adherent. This can be problematic for certain applications, forexample, when the adherent is skin or another biological surface. If theweight ratio of the acrylic diblock copolymer to acrylic triblockcopolymer is less than 65:35, then the adhesive composition tends to betoo rigid and tends to have insufficient tack for many applications.

The adhesive composition can have low shear. The low shear can bedefined quantitatively, for example, as having a particular hold time onstainless steel when a 0.5 inch by 0.5 inch tape is adhered by way ofthe adhesive composition to stainless steel and a 250 gram weight isattached to the tape. In such cases, an acceptable quantitative shearcan be measured by the hold time, that is, time that the adhesivesupports the 250 grams mass before failure. Acceptable hold times undersuch tests can be no more than 3,000 minutes, no more than 2,500minutes, no more than 2,000 minutes, no more than 1,500 minutes, no morethan 1,000 minutes, no more than 750 minutes, no more than 600 minutes,no more than 500 minutes, no more than 400 minutes, no more than 300minutes, no more than 250 minutes, no more than 200 minutes, no morethan 150 minutes, or no more than 100 minutes. Acceptable hold times canalso be at least 1 minute, at least 2 minutes, at least 5 minutes, atleast 10 minutes, at least 15 minutes, at least 30 minutes, at least 45minutes, at least 60 minutes, at least 90 minutes, at least 120 minutes,at least 180 minutes, at least 200 minutes, at least 240 minutes, atleast 300 minutes, or at least 350 minutes. The low shear can also bedefined qualitatively. For example, when the adhesive is used to securean article to an adherent, the article can be readily removed by hand.

The adhesive composition can further comprise one or more of at leastone plasticizer, at least one tackifier, and at least one filler.Plasticizers can include phthalate esters, adipate esters, phosphateesters, citrate esters, sugar derivatives, poly(ethylene glycol), andpoly(ethylene glycol) functionalized organic molecules. Exemplaryplasticizers include, but are not limited to, one or more of phthalateester, bis(2-ethylhexyl)adipate, dimethyl adipate, monomethyl adipate,dioxtyl adipate, dibutyl sebacate, dibutyl maleate, biisobutyl maleate,benzoates, terephthalates, 1,2-cyclohexane dicarboxylic acid diisononylester, epoxidized vegetable oil, alkyl sulphonic acid phenyl ester,N-ethyl toluene sulfonamide, N-(2-hydroxypropyl)benzene sulfonamide,N-(n-butyl benzene sulfonamide, sucrose acetate isobutyrate, tricresylphosphate, tributyl phosphate, triethylene glycol dihexanoate,tetraethylene glycol diheptanoate, triethyl citrate, acetyl triethylcitrate, tributyl citrate, acetyl tributyl citrate, trioctyl citrate,acetyl trioctyl citrate, trihexyl citrate, acetyl trihexyl citrate,butyryl trihexyl citrate, trimethyl citrate, sucrose acetateisobutyrate, and acetylated monoglyceride.

Tackifiers can include rosins, hydrocarbon resins, terpenes, and MQsilicate resins. Exemplary tackifiers can include one or more of rosin,rosin derivative, terpenes, modified terpenes, C5 aliphatic resins, C9aromatic resins, C5/C9 aliphatic/aromatic resins, hydrogenatedhydrocarbon resin, terpene-phenol resin, poly(alpha-methylstyrene) (AMS)resin, poly(styrene) resins (also known as ‘Pure Monomer Resins),copolymers of (alpha-methylstyrene) and styrene resins, and phenolicmodified AMS resins, and MQ silicate resin. Some suitable tackifiers areobtainable under the trade designation KRISTALEX 1120, 3100, 5140 andPLASTOLYN 240, 290 (Eastman Chemical Company), YS RESIN SX 100 (YasuharaChemical Co., Ltd., Hiroshima, Japan), NORSOLENE W-100 (Cray ValleyDivision of Total Petrochemicals and Refining, Inc., Houston, Tex.,USA), SYLVARES 520, 525, 540, SA85, SA100, SA120, SA140, TP115P (ArizonaChemical Inc. Jacksonville, Fla., USA), and PICCOPLASTIC A5 HydrocarbonResin (Eastman Chemical Company, Kingsport, Tenn., USA).

Fillers can include any appropriate inert inorganic particle. Exemplaryfillers include one or more of alumina trihydrate, talc, ceramic, rock,coal, ground glass, glass beads, particulate plastics, non-catalyticmetals, sand, silica, calcium carbonate, and magnesium carbonate.

The total amount of plasticizer, tackifier, and filler, if any areincluded in the composition, can be up to 45% by weight of the adhesivecomposition, for example, up to 40% by weight of the adhesivecomposition, up to 35% by weight of the adhesive composition, up to 30%by weight of the adhesive composition, up to 25% by weight of theadhesive composition, up to 20% by weight of the adhesive composition,up to 15% by weight of the adhesive composition, up to 10% by weight ofthe adhesive composition, up to 5% by weight of the adhesivecomposition, up to 2% by weight of the adhesive composition, or up to 1%by weight of the adhesive composition. If present, the total amount ofplasticizer, tackifier, and filler can be no less than 0.001% by weight,no less than 0.005% by weight, no less than 0.01% by weight, no lessthan 0.05% by weight, no less than 0.1% by weight, no less than 0.5% byweight, no less than 1% by weight, no less than 1.5% by weight, or noless than 2% by weight of the adhesive composition.

Thus, the components of exemplary adhesive compositions can range inamount from those containing 90% acrylic diblock copolymer, 10% acrylictriblock copolymer, and no tackifier, plasticizer, or filler, to thosecontaining 42.25% acrylic triblock copolymer, 22.75% acrylic diblockcopolymer, and 45% of a combination of tackifier, plasticizer, andfiller.

An adhesive article can comprise a substrate and an adhesivecomposition, such as the adhesive compositions disclosed herein. Theadhesive is disposed as an adhesive layer adjacent to the substrate. Theadhesive layer can be in contact with the substrate or separated fromthe substrate by another layer such as a primer layer or adhesionpromoting layer. The substrate can be any suitable substrate for theadhesive article, for example, a polymeric substrate, a fabricsubstrate, such as a woven fabric substrate or a non-woven fabricsubstrate, a cellulose-based substrate, or the like. Typical substratescan include one or more of a polyurethane substrate, a polyethylenesubstrate, a polyester substrate, a cellulosic substrate, a polyamidesubstrate, and a poly(ethylene terephthalate) substrate. The adhesivearticle can further comprise one or more topically administrablepharmaceutically active agents. Exemplary topically administrablepharmaceutically active agents include anti-microbials, anti-fungals,anti-inflammatory agents, including but not limited to steroidalanti-inflammatory agents and non-steroidal anti-inflammatory drugs(NSAIDs), vitamins, beneficial oils, moisturizers, and the like.Specific topically administrable pharmaceutically active agents includeiodine, povidone-iodine, silver, salicylic acid or salts thereof,acetylsalicylic acid or salts thereof, chlorhexidine, such aschlorhexidine gluconate, sulfacetamide and salts thereof, erythromycin,neomycin, polymyxin, bacitracin, retapamulin, mupirocin, gentamicin,mefenide, lidocaine, tetracycline, benzoic acid, ciclopirox olamine,undecylenic alkanolamide, bifonazole, clotramazoel, econazole,ketoconazole, miconazole, tioconazole, terbinafine, tolciclate,tolnaftate, tymol, sulfacetamide, almond oil, argan oil, avocado oil,camelina oil, coconut oil, jojoba oil, rose oil, sesame seed oil, sheaoil, hemp seed oil, macadamia nut oil, lanolin, vitamins such as vitaminA, vitamin A palmitate, vitamin B3, vitamin C, and tocopherols andesters thereof, such as alpha-tocopherol and alpha-tocopheryl acetate.Such topically administrable pharmaceutically active agents can be usedin any suitable amount, such as up to 20% by weight, up to 15% byweight, up to 10% by weight, up to 5% by weight, up to 2% by weight, orup to 1% by weight, based on the total weight of the diblock andtriblock copolymers.

An adhesive article containing an adhesive composition as describedherein can be used, for example, in medical, veterinary, pharmaceutical,or surgical procedures. For example, an adhesive article can be placedover a wound to treat a wound. The adhesive article can also be placedover a catheter, intravenous needle, or inter-arterial needle that is atleast partially inserted into a subject, for example, into a lumen of asubject, in order to stabilize the catheter, intravenous needle, orinter-arterial needle. The adhesive composition can also be used tosecure a medical device on or to a subject.

Adhesive articles comprising the adhesive composition described hereincan provide low or minimal edge lift over an applicable period of time.An applicable period of time can be, for example, no more than twoweeks, no more than twelve days, no more than ten days, no more than oneweek, no more than five days, no more than three days, or no more thantwo days. An applicable period of time can also be one day or greater,two days or greater, three days or greater, five days or greater, or oneweek or greater. Exemplary applicable periods of time include two weeks,twelve days, ten days, one week, five days, three days, two days, or oneday. Low or minimal edge lift is particularly useful when the adhesivearticle is used as a wound dressing, for stabilizing a catheter,intravenous, or inter-arterial needle, or for affixing a medical device.

EXEMPLARY EMBODIMENTS

Exemplary embodiments of the present disclosure may take on variousmodifications and alterations without departing from the spirit andscope of the present disclosure. Accordingly, it is to be understoodthat the particular embodiments described below are not intended to belimiting.

Embodiment 1

An adhesive composition comprising:

-   -   (a) an acrylic triblock copolymer A-B-A comprising from 20% to        55% by weight A blocks and 45% to 80% by weight B block; and    -   (b) an acrylic diblock copolymer A-B comprising from 5% to 30%        by weight A block and 70% to 95% by weight B block, wherein

each A block is independently a polymeric block having a glasstransition temperature of at least 50° C.;

each A block independently comprises at least one poly(meth)acrylate;

each B block is independently a polymeric block having a glasstransition temperature no greater than 20° C.;

each B block independently comprises at least one poly(meth)acrylate;and

the weight ratio of the acrylic diblock copolymer to the acrylictriblock copolymer is from 65:35 to 90:10.

Embodiment 2

The adhesive composition of embodiment 1, wherein the acrylic diblockcopolymer A block is a homopolymer.

Embodiment 3

The adhesive composition of any of the preceding embodiments, whereinthe acrylic diblock copolymer A block comprises a poly(alkyl(meth)acrylate).

Embodiment 4

The adhesive composition of embodiment 3, wherein the alkyl(meth)acrylate has a C₁ to C₃ alkyl.

Embodiment 5

The adhesive composition of embodiment 4, wherein the alkyl is methyl.

Embodiment 6

The adhesive composition of any of the preceding embodiments, whereinthe acrylic diblock copolymer A block comprises poly(alkylmethacrylate).

Embodiment 7

The adhesive composition of embodiment 6, wherein the poly(alkylmethacrylate) is poly(methyl methacrylate).

Embodiment 8

The adhesive composition of any of the preceding embodiments, whereinthe acrylic diblock copolymer B block is a homopolymer.

Embodiment 9

The adhesive composition of any of the preceding embodiments, whereinthe acrylic diblock copolymer B block comprises poly(alkyl(meth)acrylate).

Embodiment 10

The adhesive composition of embodiment 9, wherein the alkyl(meth)acrylate has a C₂ to C₁₆ alkyl.

Embodiment 11

The adhesive composition of embodiment 10, wherein the C₂ to C₁₆ alkylis C₄ to C₁₂ alkyl.

Embodiment 12

The adhesive composition of embodiment 11, wherein the C₄ to C₁₂ alkylis C₄ to C₈ alkyl.

Embodiment 13

The adhesive composition of embodiment 12, wherein the C₄ to C₈ alkylalkyl is n-butyl.

Embodiment 14

The adhesive composition of embodiment 12, wherein the C₄ to C₈ alkyl is2-ethylhexyl.

Embodiment 15

The adhesive composition of embodiment 12, wherein the C₄ to C₈ alkyl isisooctyl.

Embodiment 16

The adhesive composition of any of the preceding embodiments, whereinthe acrylic diblock copolymer B block comprises poly(alkyl acrylate).

Embodiment 17

The adhesive composition of embodiment 16, wherein the poly(alkylacrylate) is poly(n-butyl acrylate).

Embodiment 18

The adhesive composition of embodiment 16, wherein the poly(alkylacrylate) is poly(isooctyl acrylate), poly(2-octyl acrylate), orpoly(isononyl acrylate).

Embodiment 19

The adhesive composition of embodiment 16, wherein the poly(alkylacrylate) is poly(2-ethylhexyl acrylate).

Embodiment 20

The adhesive composition of any of the preceding embodiments, wherein atleast one of the acrylic triblock copolymer A blocks is a homopolymer.

Embodiment 21

The adhesive composition any of the preceding embodiments, wherein bothof the acrylic triblock copolymer A blocks are homopolymers.

Embodiment 22

The adhesive composition of any of the preceding embodiments, wherein atleast one acrylic triblock copolymer A block comprises poly(alkyl(meth)acrylate).

Embodiment 23

The adhesive composition of embodiment 22, wherein both acrylic triblockcopolymer A blocks comprise poly(alkyl (meth)acrylate).

Embodiment 24

The adhesive composition of any of embodiments 22-23, wherein the alkyl(meth)acrylate has a C₁ to C₃ alkyl.

Embodiment 25

The adhesive composition of embodiment 24, wherein the alkyl is methyl.

Embodiment 26

The adhesive composition of any of the preceding embodiments, whereinboth of the acrylic triblock A blocks comprise poly(alkyl methacrylate).

Embodiment 27

The adhesive composition of embodiment 26, wherein the poly(alkylmethacrylate) is poly(methyl methacrylate).

Embodiment 28

The adhesive composition of any of the preceding embodiments, whereinthe acrylic triblock copolymer B block comprises poly(alkyl(meth)acrylate).

Embodiment 29

The adhesive composition of embodiment 28, wherein the alkyl(meth)acrylate has a C₂ to C₁₆ alkyl.

Embodiment 30

The adhesive composition of embodiment 29, wherein the C₂ to C₁₆ alkylis C₄ to C₁₂ alkyl.

Embodiment 31

The adhesive composition of embodiment 30, wherein the C₄ to C₁₂ alkylis C₄ to C₉ alkyl or C₄ to C₈ alkyl.

Embodiment 32

The adhesive composition of embodiment 31, wherein the C₄ to C₈ alkyl isn-butyl.

Embodiment 33

The adhesive composition of embodiment 31, wherein the C₄ to C₈ alkyl is2-ethylhexyl acrylate.

Embodiment 34

The adhesive composition of embodiment 31, wherein the C₄ to C₉ alkyl isisooctyl acrylate, or isononyl acrylate, or 2-octyl acrylate.

Embodiment 35

The adhesive composition of any of the preceding embodiments, whereinthe acrylic triblock copolymer B block comprises poly(alkyl(meth)acrylate).

Embodiment 36

The adhesive composition of embodiment 35, wherein the poly(alkyl(meth)acrylate) is poly(n-butyl acrylate).

Embodiment 37

The adhesive composition of embodiment 35, wherein the poly(alkylacrylate) is poly(isooctyl acrylate), poly(2-octyl acrylate), orpoly(isononyl acrylate).

Embodiment 38

The adhesive composition of embodiment 35, wherein the poly(alkylacrylate) is poly(2-ethyl hexyl acrylate).

Embodiment 39

The adhesive composition of any of the preceding embodiments, whereinthe adhesive composition does not contain a chemical crosslinker.

Embodiment 40

The adhesive composition of any of the preceding embodiments, whereinthe weight ratio of the acrylic diblock to the acrylic triblock is from65:35 to 80:20.

Embodiment 41

The adhesive composition of any of embodiments 1-39, wherein the weightratio of the acrylic diblock to the acrylic triblock is from 70:30 to90:10.

Embodiment 42

The adhesive composition of any of embodiments 1-39, wherein the weightratio of the acrylic diblock to the acrylic triblock is from 70:30 to80:20

Embodiment 43

The adhesive composition of any of embodiments 1-39, wherein the weightratio of the acrylic diblock to the acrylic triblock is from 75:25 to90:10.

Embodiment 44

The adhesive composition of any of embodiments 1-39, wherein the weightratio of the acrylic diblock to the acrylic triblock is from 75:25 to80:20.

Embodiment 45

The adhesive composition of any of embodiments 1-39, wherein the amountof acrylic diblock copolymer is 65% by weight or greater relative to thetotal weight of the acrylic diblock and the acrylic triblock.

Embodiment 46

The adhesive composition of any of embodiments 1-39, wherein the amountof acrylic diblock copolymer is 70% by weight or greater relative to thetotal weight of the acrylic diblock and the acrylic triblock.

Embodiment 47

The adhesive composition of any of embodiments 1-39, wherein the amountof acrylic diblock copolymer is 80% by weight or greater relative to thetotal weight of the acrylic diblock and the acrylic triblock.

Embodiment 48

The adhesive composition of any of embodiments 1-39, wherein the amountof acrylic diblock copolymer is 85% by weight or greater relative to thetotal weight of the acrylic diblock and the acrylic triblock.

Embodiment 49

The adhesive composition of any of embodiments 1-39 or 45-48, whereinthe amount of the acrylic diblock is no more than 90% by weight relativeto the total weight of the acrylic diblock and the acrylic triblock.

Embodiment 50

The adhesive composition of embodiment 49, wherein the amount of theacrylic diblock is no more than 85% by weight relative to the totalweight of the acrylic diblock and the acrylic triblock.

Embodiment 51

The adhesive composition of embodiment 50, wherein the amount of theacrylic diblock is no more than 80% by weight relative to the totalweight of the acrylic diblock and the acrylic triblock.

Embodiment 52

The adhesive composition of embodiment 51, wherein the amount of theacrylic diblock is no more than 75% by weight relative to the totalweight of the acrylic diblock and the acrylic triblock.

Embodiment 53

The adhesive composition of embodiment 52, wherein the amount of theacrylic diblock is no more than 70% by weight relative to the totalweight of the acrylic diblock and the acrylic triblock.

Embodiment 54

The adhesive composition of any of embodiments 1-39 or 45-52, whereinthe amount of the acrylic triblock is 15% by weight, 20% by weight, orgreater relative to the total weight of the acrylic diblock and theacrylic triblock.

Embodiment 55

The adhesive composition of embodiment 53, wherein the amount of theacrylic triblock is 25% by weight or greater relative to the totalweight of the acrylic diblock and the acrylic triblock.

Embodiment 56

The adhesive composition of any of the preceding embodiments, whereinthe amount of the acrylic triblock is no more than 30% by weightrelative to the total weight of the acrylic diblock and the acrylictriblock.

Embodiment 57

The adhesive composition of embodiment 56, wherein the amount of theacrylic triblock is no more than 25% by weight relative to the totalweight of the acrylic diblock and the acrylic triblock.

Embodiment 58

The adhesive composition of embodiment 57, wherein the amount of theacrylic triblock is no more than 20% by weight relative to the totalweight of the acrylic diblock and the acrylic triblock.

Embodiment 59

The adhesive composition of embodiment 58, wherein the amount of theacrylic triblock is no more than 15% by weight relative to the totalweight of the acrylic diblock and the acrylic triblock.

Embodiment 60

The adhesive composition of any of the preceding embodiments, furthercomprising one or more additives.

Embodiment 61

The adhesive composition of embodiment 60, wherein the at least one ofthe one or more additives is compatible with at least one A polymerblock, at least one B polymer block, or at least one A polymer block andat least one B polymer block.

Embodiment 62

The adhesive composition of any of the preceding embodiments, furthercomprising one or more of at least one plasticizer, at least onetackifier, and at least one filler.

Embodiment 63

The adhesive composition of any of the preceding embodiments, furthercomprising at least one plasticizer.

Embodiment 64

The adhesive composition of embodiment 63, wherein the at least oneplasticizer includes one or more of phthalate esters, adipate esters,phosphate esters, citrate esters, sugar derivatives, poly(ethyleneglycol), and poly(ethylene glycol) functionalized organic molecules.

Embodiment 65

The adhesive composition of any of embodiments 63-64, wherein the atleast one plasticizer comprises one or more of phthalate ester,bis(2-ethylhexyl)adippate, dimethyl adipate, monomethyl adipate, dioxtyladipate, dibutyl sebacate, dibutyl maleate, biisobutyl maleate,benzoates, terephthalates, 1,2-cyclohexane dicarboxylic acid diisononylester, epoxidized vegetable oil, alkyl sulphonic acid phenyl ester,N-ethyl toluene sulfonamide, N-(2-hydroxypropyl)benzene sulfonamide,N-(n-butyl benzene sulfonamide, sucrose acetate isobutyrate, tricresylphosphate, tributyl phosphate, triethylene glycol dihexanoate,tetraethylene glycol diheptanoate, triethyl citrate, acetyl triethylcitrate, tributyl citrate, acetyl tributyl citrate, trioctyl citrate,acetyl trioctyl citrate, trihexyl citrate, acetyl trihexyl citrate,butyryl trihexyl citrate, trimethyl citrate, and acetylatedmonoglyceride.

Embodiment 66

The adhesive composition of any of the preceding embodiments, furthercomprising at least one tackifier.

Embodiment 67

The adhesive composition of embodiment 66, wherein the at least onetackifier comprises one or more of rosin, rosin derivative, rosin ester,terpene, modified terpene, C5 aliphatic resin, C9 aromatic resin, C5/C9aliphatic/aromatic resin, hydrogenated hydrocarbon resin, terpene-phenolresin, poly(alpha-methylstyrene) (AMS) resin, poly(styrene) resins (alsoknown as ‘Pure Monomer Resins), copolymers of (alpha-methylstyrene) andstyrene resins, and phenolic modified AMS resins, and MQ silicate resin.

Embodiment 68

The adhesive composition of any of the preceding embodiments, furthercomprising at least one filler.

Embodiment 69

The adhesive composition of embodiment 68, wherein the at least onefiller comprises at least one inert inorganic particles and one or moreinert polymeric particles.

Embodiment 70

The adhesive composition of any of embodiments 68-69, wherein the atleast one filler comprises one or more of alumina trihidrate, talc,ceramic, rock, coal, ground glass, glass beads, particulate plastics,non-catalytic metals, sand, silica, calcium carbonate, and magnesiumcarbonate.

Embodiment 71

The adhesive composition of any of embodiments 62-70, wherein the one ormore of at least one plasticizer, at least one tackifier, and at leastone filler is present in an amount greater than 0.001% but no greaterthan 30% by weight of the adhesive composition.

Embodiment 72

An article comprising:

a substrate; and

the adhesive composition of any of the preceding embodiments disposedadjacent to the substrate.

Embodiment 73

The article of embodiment 72, wherein the substrate comprisespolyurethane.

Embodiment 74

The article of embodiment 73, wherein the substrate comprisespoly(ethylene terephthalate).

Embodiment 75

A wound dressing comprising the adhesive of any of embodiments 1-71, orthe article of any of embodiments 72-74, adapted to adhere to skin.

Embodiment 76

The adhesive of any of embodiments 1-71, or the article of any ofembodiments 72-74, or the wound dressing of embodiment 75, furthercomprising one or more topically administrable pharmaceutically activeagents.

Embodiment 77

A method of treating a wound, comprising applying the adhesive of any ofembodiments 1-71, or the article of any of embodiments 72-74, or thewound dressing of embodiment 75 to the wound.

Embodiment 78

A method of stabilizing a catheter, comprising:

applying the adhesive of any of embodiments 1-71, or the article of anyof embodiments 72-74, or the wound dressing of embodiment 75 over thecatheter, wherein the catheter is at least partially inserted into apatient.

Embodiment 79

A method of stabilizing an intravenous or intra-arterial needle,comprising:

applying the adhesive any of embodiments 1-71, or the article of any ofembodiments 72-74, or the wound dressing of embodiment 75 over anintravenous or intra-arterial needle, wherein the intravenous orintra-arterial needle is at least partially inserted into a patient.

Embodiment 80

A method of affixing a medical device, comprising:

contacting the medical device with an adhesive any of embodiments 1-71,or the article of any of embodiments 72-74, or the wound dressing ofembodiment 75; and

affixing the medical device to a subject.

EXAMPLES

All parts, percentages, ratios, and the like used in the Examples are byweight unless indicated otherwise.

Materials

Abbreviation Description and Source LA2330 An acrylic triblock copolymerA-B-A, where A is poly(methyl methacrylate) (“PMMA”) and B ispoly(n-butyl acrylate) (“PBA”) with 24 weight % PMMA, a number averagemolecular weight of 97.5 kDa, and a weight average molecular weight of105.3 kDa as determined by gel permeation chromatography. Available fromKuraray America Inc., Houston, TX, under the trade designation “KURARITYLA2330” LA4285 An acrylic triblock copolymer A-B-A (where A is PMMA andB is PBA) with 51 weight % PMMA, a number average molecular weight of 48kDa, and a weight average molecular weight 57 kDas determined by gelpermeation chromatography. Available from Kuraray America, Inc.,Houston, TX, under the trade designation “KURARITY LA4285” LA2140 Anacrylic triblock copolymer A-B-A where A is PMMA and B is PBA with 24weight % PMMA, a number average molecular weight of 60 kDa, and a weightaverage molecular weight of 66 kDa as determined by gel permeationchromatography. Available from Kuraray America Inc. Houston, TX, underthe trade designation “KURARITY LA2140” LA1114 An acrylic diblockcopolymer A-B where A is PMMA and B is PBA with 7 weight % PMMA, anumber average molecular weight of 50 kDa, and a weight averagemolecular weight of 60 kDa as determined by gel permeationchromatography. Available from Kuraray America Inc., Houston, TX, underthe trade designation “KURARITY LA1114” Toluene Toluene, available fromAvantor Performance Materials, Center Valley, PA YS RESIN SX100 A purestyrene resin tackifying resin, available from Yasuhara Chemical,Hiroshima, JP, under the trade designation “YS RESIN SX100” SYLVALITE Arosin ester tackifier, available from Arizona Chemical, Jacksonville,FL, RE80HP under the trade designation “SYLVALITE RE80HP” SAIB Sucroseacetate isobutyrate, a plasticizer available from Eastman ChemicalCompany, Kingsport, TN ESTANE 58309 Thermoplastic polyurethane elastomeravailable in pellet form from Lubrizol Advanced Materials, Inc.,Cleveland, OH, under the trade designation “ESTANE 58309” 3SAB PRIMED 50micrometer thick primed polyester film, available from Mitsubishi PETPolyester Film, Greer, South Carolina, under the trade designation “3SABFILM PRIMED PET FILM”

Sample Preparation Method: Coated Adhesive Tapes (Examples andComparative Examples)

Acrylic block copolymer blends were combined with any tackifiers andother additives being used for the particular experiment. The blockcopolymers (and tackifier or other additive, if included) were combinedin the amounts specified in Table 1 to Table 6, below. The resultingcompositions were dissolved in toluene to form 50 weight percent solidssolutions, and these solutions were knife coated on a siliconized paperrelease liner. The coatings were dried in an oven at 70° C. for 10minutes. The final thickness of the layer of dried adhesive wasnominally 38 micrometers.

Laminated samples for the 180° Peel Adhesion Test (see below) and theShear Strength Test (see below) were prepared by laminating a 50micrometer poly(ethylene terephthalate) film (i.e., 3SAB PRIMED PETFILM) to the layer of dried adhesive.

Laminated samples for the Adhesion to Skin Test (see below) wereprepared by laminating the dried adhesive prepared for the 180° PeelAdhesion Test to a 20 micrometer thick polyurethane film. Thepolyureathane film was prepared by extrusion coating ESTANE 58309(Lubrizol, Wickliffe, Ohio) onto a polycoated-paper carrier for support.

All sample tapes were conditioned in a constant temperature (25° C.) andhumidity room (50% relative humidity) for at least 24 hours beforetesting.

Test Methods 180° Peel Adhesion Test

The 180° peel adhesion test was similar to the test method described inASTM D3330 Method E. The adhesive coatings were laminated to 3SAB PRIMEDPET FILM, as described in the above Sample Preparation Method. Tapes 1inch (˜2.5 cm) wide were cut from the laminated samples. Stainless steeltesting substrates were cleaned with reagent grade n-heptane followed bymethyl ethyl ketone and clean lint-free absorbent tissue. The releaseliner was removed and the tape was rolled down onto a stainless steelplate with a 4.5 lb (˜2 kg) roller. The sample was allowed to dwell forone minute before peeling at 12 inches (˜30 cm) per minute using anIMASS 2000 slip/peel tester (available from Instrumentors, Inc.,Strongsville, Ohio). For each adhesive composition, two sample tapeswere tested, and the reported peel adhesion value was an average of thepeel adhesion value for each of the two sample tapes.

Shear Strength Test

The shear strength test was similar to the test method described in ASTMD3654 Method A. The adhesive coatings were laminated to 3SAB PRIMED PETFILM, as described in the above Sample Preparation Method. Tapes 0.5inch (˜1.3 cm) wide were cut from the laminated samples. The tape samplewas rolled down onto a cleaned stainless steel panel using a 4.5 lb (˜2kg) roller. A hook was attached to the unsupported end of the tape andthe sample adhered to the panel was trimmed to 0.5 inch (˜1.3 cm) by 0.5inch (˜1.3 cm). The sample was allowed to dwell for one minute prior thetest panel being placed on the test stand. A 250 gram mass was appliedto the hook. The time to failure of the sample was measured intriplicate and reported as an arithmetic mean in minutes.

Adhesion to Skin Test

The adhesive coatings were laminated to a 20 micrometer thickpolyurethane film, prepared from ESTANE 58309, as described in the abovePreparation Method. Tapes 2.5 cm by 7.5 cm were cut from the laminatedsamples. The release liner was removed from the sample tape strip andthe exposed adhesive was placed against the distal forearm of a healthyhuman volunteer. Tape strips were rolled down with a 4.5 lb (˜2 kg)roller. Visual assessments of a sample tape edge lift were recordedafter 48 hours of wear. Visual assessment criteria used to score thetape edge lift was as follows:

Tape Edge Lift:

0=No sample area has lifted from the skin

1=>1-25% of the sample area has lifted from the skin

2=26-50% of the sample area has lifted from the skin

3=51-75% of the sample area has lifted from the skin

4=76-99% of the sample area has lifted from the skin

5=100% of the sample has lifted from the skin (i.e., the sample hasfallen off)

After 48 hours of dwell time, the samples were peeled from the skin at180° at approximately 90 inches (about 230 cm) per minute peel rate. Thepresence of residue was noted using the following visual assessmentscale:

Residue:

0=0% of area under the sample has left residue on skin

1=1-25% of area under the sample has left residue on skin

2=26-50% of area under the sample has left residue on skin

3=51-75% of area under the sample has left residue on skin

4=76-100% of area under the sample has left residue on skin

Examples EX-1 to EX-4 and Comparative Examples CE-1 to CE-3 had thecompositions and test results as summarized in Table 1.

TABLE 1 Adhesion and Shear Adhesion to Skin Acrylic on Steel Testcopolymer, 180° Peel Shear Tape weight ratio Adhesion Strength EdgeSample LA2330 LA1114 (g/cm) (min) Lift Residue EX-1 0.3 0.7 127 2126 2 0EX-2 0.2 0.8 202 463 2 0 EX-3 0.15 0.85 301 258 0 1 EX-4 0.1 0.9 208 150 2 CE-1 0.5 0.5 239 4814 5 0 CE-2 0.4 0.6 300 1816 5 0 CE-3 0.05 0.95286 4 0 4

Examples EX-5 to EX-13 and Comparative Examples CE-4 to CE-7 included arosin ester tackifier additive (in parts per hundred (“pph”) relative tothe 100 parts acrylic block copolymer), with compositions and test dataas summarized in Table 2.

TABLE 2 Adhesion and Shear on Steel 180° Rosin Peel Ester Ad- Adhesionto Acrylic Tackifier, he- Skin Test copolymer, pph sion Shear Tapeweight ratio SYLVILITE (g/ Strength Edge Res- Sample LA2330 LA1114RE80HP cm) (min) Lift idue EX-5 0.3 0.7 11.1 246 1094 2 0 EX-6 0.2 0.811.1 318 276 0 0 EX-7 0.1 0.90 11.1 227 19 0 2 EX-8 0.3 0.7 25 329 13872 0 EX-9 0.2 0.8 25 524 609 1 0 EX-10 0.1 0.90 25 302 22 0 2 EX-11 0.350.65 42.9 560 1200 1 0 EX-12 0.21 0.79 42.9 495 500 0 0 EX-13 0.14 0.8642.9 515 175 0 0 CE-4 0.5 0.5 11.1 185 1199 5 0 CE-5 0.4 0.6 11.1 2692177 5 0 CE-6 0.5 0.5 25 262 10000 5 0 CE-7 0.4 0.6 25 334 3386 5 0

Examples EX-14 to EX-21 and Comparative Examples CE-8 to CE-14 includeda plasticizer additive, with compositions and test data as summarized inTable 3.

TABLE 3 Adhesion and Shear Adhesion on Steel to Skin Acrylic Plasti-180° Test copolymer, cizer, Peel Shear Tape weight ratio pph AdhesionStrength Edge Res- Sample LA2330 LA1114 SAIB (g/cm) (min) Lift idueEX-14 0.3 0.7 11.1 325 211 2 0 EX-15 0.2 0.8 11.1 555 245 0 0 EX-16 0.130.87 11.1 631 54 1 1 EX-17 0.1 0.90 11.1 504 7 0 2 EX-18 0.3 0.7 25 633238 1 0 EX-19 0.2 0.8 25 1010 104 0 0 EX-20 0.1 0.90 25 580 1 0 2 EX-210.35 0.65 42.9 652 265 1 0 CE-8 0.4 0.6 11.1 695 2000 3 0 CE-9 0.05 0.9511.1 256 2 0 4 CE-10 0.5 0.5 25 626 2306 5 0 CE-11 0.4 0.6 25 665 3035 30 CE-12 1 0 42.9 338 10000 5 0 CE-13 0.71 0.29 42.9 674 854 5 0 CE-140.5 0.5 42.9 681 527 2 0

Examples EX-22 to EX-26 and Comparative Examples CE-15 to CE-16 includeda tackifier resin additive, with compositions and test data assummarized in Table 4.

TABLE 4 Adhesion and Tackifier Shear on Steel Resin, 180° Adhesion toAcrylic pph Peel Skin Test copolymer, YS Ad- Shear Tape weight ratioRESIN hesion Strength Edge Resi- Sample LA2330 LA1114 SX100 (g/cm) (min)Lift due EX-22 0.28 0.72 11.1 688 986 1 0 EX-23 0.22 0.78 11.1 858 416 00 EX-24 0.25 0.75 25.0 967 992 0 0 EX-25 0.15 0.85 17.0 911 758 0 0EX-26 0.1 0.9 17.6 955 275 0 2 CE-15 0.36 0.64 17.6 951 4557 3 0 CE-160.47 0.53 17.6 807 6842 5 0

Examples EX-27 to EX-29 had the compositions and test results assummarized in Table 5.

TABLE 5 Adhesion and Shear on Steel Adhesion to 180° Skin Test Acryliccopolymer, Peel Shear Tape weight ratio Adhesion Strength Edge SampleLA4285 LA1114 (g/cm) (min) Lift Residue EX-27 0.20 0.80 171 7 0 0 EX-280.15 0.85 144 1 0 1 EX-29 0.1 0.90 157 6 0 1

Examples EX-30 to EX-33 had the compositions and test results assummarized in Table 6.

TABLE 6 Adhesion and Adhesion to Skin Shear on Steel Test Acryliccopolymer, 180° Peel Shear Tape weight ratio Adhesion Strength EdgeSample LA2140 LA1114 (g/cm) (min) Lift Residue EX-30 0.3 0.7 249 1846 10 EX-31 0.2 0.8 355 294 1 0 EX-32 0.15 0.85 573 248 0 0 EX-33 0.1 0.9442 54 0 1

As shown in the above tables, samples having acrylic diblock and acrylictriblock copolymers with the relative amounts of A and B blocksdescribed herein, wherein the diblock and triblock copolymers arepresent in the ratios described herein, have superior peel and shearproperties. Such polymers also have better results in edge lift andresidue tests when applied to human skin. In particular, such sampleshave acceptable values for all of these parameters. By comparison, theComparative Examples give unacceptable results with respect to at leastone of these parameters. For instance, despite having a higher adhesionthan Example 1, Comparative Example 1 has an unacceptable edge lift.Also, while Example 14 has acceptably low shear and edge lift,Comparative Example 8, which differs from Example 14 only in that itfeatures a ratio of acrylic diblock to triblock copolymers that isslightly outside of the requisite range, has a sheer that is nearly 100times that of Example 8 as well as an unacceptably high edge lift. Thus,adhesives having the combination of acrylic diblock and triblockcopolymers as described herein surprisingly provide an acceptablebalance of all of these parameters.

While the specification has described particular embodiments in detailto assist the artisan's understanding, those skilled in the art willreadily conceive of various alternatives, variations, and equivalents ofthe description. It should therefore be understood the protection soughtis to be limited only by the appended claims and not by the particularembodiments and discussed herein.

1. An adhesive composition comprising: an acrylic triblock copolymerA-B-A comprising from 20% to 55% by weight of A blocks and 45% to 80% byweight of B block; and an acrylic diblock copolymer A-B comprising from5% to 30% by weight of A block and 70% to 95% by weight of B block,wherein each A is independently a polymeric block having a glasstransition temperature of at least 50° C.; and each A independentlycomprises at least one poly(meth)acrylate; and each B is independently apolymeric block having a glass transition temperature no greater than20° C. and; each B independently comprises at least onepoly(meth)acrylate; and the weight ratio of the acrylic diblockcopolymer to the acrylic triblock copolymer is from 70:30 to 90:10. 2.The adhesive composition of claim 1, wherein the acrylic diblockcopolymer A block comprises poly(alkyl (meth)acrylate).
 3. The adhesivecomposition of claim 2, wherein the poly(alkyl (meth)acrylate) ispoly(methyl methacrylate).
 4. The adhesive composition of claim 1,wherein the acrylic diblock copolymer B block comprises poly(alkyl(meth)acrylate).
 5. The adhesive composition of claim 4, wherein thealkyl (meth)acrylate has a C₄ to C₉ alkyl or a C₄ alkyl to C₈ alkyl. 6.The adhesive composition of claim 5, wherein the poly(alkyl(meth)acrylate) is poly(n-butyl acrylate), poly(isooctyl acrylate),poly(2-octyl acrylate), poly(isononyl acrylate), or poly(2-ethyl hexylacrylate).
 7. The adhesive composition of claim 1, wherein at least oneof the acrylic triblock copolymer A blocks comprises poly(alkyl(meth)acrylate).
 8. The adhesive composition of claim 1, wherein both ofthe acrylic triblock copolymer A blocks comprise poly(alkyl(meth)acrylate).
 9. The adhesive composition of claim 7, wherein thepoly(alkyl (meth)acrylate) is poly(methyl methacrylate).
 10. Theadhesive composition of claim 1, wherein the acrylic triblock copolymerB block comprises poly(alkyl (meth)acrylate).
 11. The adhesivecomposition of claim 10, wherein the poly(alkyl (meth)acrylate) has a C₄alkyl to C₉ alkyl or a C₄ alkyl to C₈ alkyl.
 12. The adhesivecomposition of claim 11, wherein the poly(alkyl (meth)acrylate) ispoly(n-butyl acrylate), poly(isooctyl acrylate), poly(2-octyl acrylate),poly(isononyl acrylate), or poly(2-ethyl hexyl acrylate).
 13. Theadhesive composition of claim 1, further comprising a tackifier.
 14. Anarticle comprising: a substrate; and an adhesive layer disposed adjacentto the substrate, wherein the adhesive layer comprises the adhesivecomposition of claim
 1. 15. The article of claim 14, wherein theadhesive layer has a first surface that is attached to the substrate anda second opposite surface that is attached to a biological surface.